The present invention relates generally to a heating apparatus for an appliance. More particularly, the present invention relates to a heating apparatus for heating a subcompartment disposed in a compartment of a refrigerator so as to maintain the temperature of the subcompartment higher than that of the compartment, a refrigerator employing the heating apparatus, and a method of heating a subcompartment disposed in a compartment of a refrigerator.
Generally, a refrigerator includes a freezer compartment and a fresh food compartment, which are partitioned from each other to store various foods at low temperatures in appropriate states for a long time.
For example, the freezer compartment is used to freeze meat, poultry and fish so that they can be stored for a longer period of time. However, the food in the freezer compartment is usually frozen hard at normal freezing temperature, which makes it difficult to cut and prepare. Accordingly, a soft freezing concept has been conceived to solve this problem, which proposes a subcompartment disposed in the freezer compartment and maintains the temperature of the subcompartment higher than that of the freezer compartment, for example, around 10° F. higher that the temperature of the freezer compartment. For example, the heated subcompartment can be mounted to the door of the freezer compartment to provide a storing space having an elevated temperature. The temperature of the subcompartment should be maintained to allow easy cutting and preparing of the food as well as medium term storage.
A heated subcompartment has been used in connection with the fresh food compartment, which is suitable for storing fruit, vegetables, dairy products, chilled liquids and other food stuffs that would otherwise be spoiled at standard room temperature, but are not desired to be frozen. For example, U.S. Pat. No. 5,839,507 discloses a heated butter conditioner mounted in the door of a fresh food compartment. The temperature of the butter conditioner is maintained higher than that of the fresh food compartment to soften the surface of the butter stored in the conditioner, so as to facilitating the slicing and spreading of the butter.
Conventionally, it is necessary to provide electric wires within the door of either a freezer compartment or a fresh food compartment, for implementing an electrical connection between a major compartment and its subcompartment, thereby energizing the heating elements mounted to the subcompartment to heat the subcompartment to a desirable temperature. This configuration incurs disadvantages, which include, among others, structural complexity of the door because of the disposition of electric wires in the door. In addition, since the main board power supply of the refrigerator may not be sufficient to energize the heating element disposed in the door, an extra power supply may be needed.
Therefore, it would be desirable to provide an advantageous configuration for implementing a heated subcompartment with high heating efficiency, without requiring electrical wiring in the door of a compartment and an extra power supply.